TY - JOUR AU - V. K. Polishchuk TI - On the analytic theory of the equation $z^2u^{''}-f(z)u=0$.~I, II JO - Differencialʹnye uravneniâ PY - 1972 SP - 1779 EP - 1790 VL - 8 IS - 10 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/DE_1972_8_10_a7/ LA - ru ID - DE_1972_8_10_a7 ER -